\documentclass[final, english]{scrreprt}
\usepackage{tikz,pgfplots}
\pgfplotsset{compat=newest}
\usetikzlibrary{arrows,trees,graphs,positioning, arrows, chains, shapes, arrows.meta,decorations.pathreplacing}
\usepackage{pstricks,pst-node,pstricks-add}
\begin{document}
\begin{figure}
\centering
\begin{tikzpicture}[node distance=1.5cm]
\tikzstyle{process1} = [rectangle, minimum width=11cm, minimum height=1cm, text centered, draw=black]
\tikzstyle{process2} = [rectangle, minimum width=6cm, minimum height=1cm, text centered, draw=black]
\tikzstyle{decision} = [diamond, base, minimum width=5cm, minimum height=1cm, text centered, draw=black, aspect=2, inner xsep=0mm]
\tikzstyle{stop} = [rectangle, rounded corners, minimum width=3cm, minimum height=1cm,text centered, draw=black]
\tikzstyle{arrow} = [thick,->,>=stealth]
%Nodes erstellen
\node (start) [process1] {\begin{tabular}{c}
Box 1: Row 1 \\
Row 2
\end{tabular}};
%Process boxes
\node (p2) [process1, below of=start, yshift = -0.2cm] {Box 2};
\node (p3) [process1, below of=p2] {Box 3};
\node (p4) [process1, below of=p3] {Box 4};
\node (p5) [process1, below of=p4] {Box 5};
%decision boxes
\node (dec1) [decision, below left of=p5, yshift=-1.5cm] {\begin{tabular}{c}
Decision Box 1: Row 1 \\
Row 2 \\
Row 3 \\
Row 4
\end{tabular}};
\node (dec2) [decision, below right of=dec1, yshift=-4cm] {\begin{tabular}{c}
Decision Box 2: Row 1 \\
Aufgrund der unbekannten Option
base
in\tikzstyle{decision} = [diamond, base, minimum width=5cm, minimum height=1cm, text centered, draw=black, aspect=2, inner xsep=0mm]
ist der gezeigte Code leider nicht lauffähig. Du kannst das leicht selbst mit demAusgabe erzeugen
-Knopf testen.